A method for preparing spherical microparticles which have a smooth surface and consist entirely or partly of at least one water-insoluble linear polysaccharide, and microparticles obtainable by said method
The present invention relates to a method for preparing spherical microparticles which have a smooth surface and consist entirely or partly of at least one water-insoluble linear polysaccharide, and microparticles obtainable by said method.
The applicant""s German patent application No. 19737481.6 describes methods for preparing spherical microparticles containing water-insoluble linear polysaccharides. This method can produce, in a simple and inexpensive manner, spherical microparticles which stand out in particular due to high uniformity with respect to their shape and their diameter distribution and also due to good mechanical properties
Owing to their comparatively uniform constitution and with simultaneously good mechanical properties, these microparticles may be employed for a multiplicity of applications.
It has, however, become apparent that, depending on the intended application, a specific modification of the particle characteristics may be advantageous.
Thus it may be desirable to prepare such microparticles with a particularly smooth surface. Microparticles with smooth surfaces are particularly suitable, for example, for the application in separation methods, for example chromatography, for which a comparatively high bulk density is advantageous, or if a particular smoothing effect is to be achieved, for example for cosmetic purposes.
It is therefore an object of the present invention to provide a method which can be used for reproducibly producing in a simple manner spherical microparticles containing water-insoluble linear polysaccharides and which have, aside from a regular shape, uniform diameter distribution and also good mechanical properties, a smooth surface.
In this respect, the present invention is an advantageous inventive development of the abovementioned German patent application No. 19737481.6.
This object is achieved by a method for preparing spherical microparticles which have a smooth surface and consist entirely or partly of at least one water-insoluble linear polysaccharide by dissolving the at least one water-insoluble linear polysaccharide in a solvent or solvent mixture, introducing the solution formed into a precipitant or precipitant mixture, where appropriate cooling the mixture being produced in the process and removing the microparticles formed, wherein at least one water-soluble cellulose derivative is used as a precipitation aid.
The present invention further relates to spherical microparticles which have a smooth surface and consist entirely or partly of at least one water-insoluble linear polysaccharide, wherein the depth of irregularities on the microparticle surface is not more than 10% of the average diameter of the microparticle.